lkml.org 
[lkml]   [2005]   [Feb]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Filesystem linking protections
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1



Chris Wright wrote:
> * Lorenzo Hernández García-Hierro (lorenzo@gnu.org) wrote:
>
>>This patch adds two checks to do_follow_link() and sys_link(), for
>>prevent users to follow (untrusted) symlinks owned by other users in
>>world-writable +t directories (i.e. /tmp), unless the owner of the
>>symlink is the owner of the directory, users will also not be able to
>>hardlink to files they do not own.
>>
>>The direct advantage of this pretty simple patch is that /tmp races will
>>be prevented.
>
>
> The disadvantage is that it can break things and places policy in the
> kernel.
>

It can break things, yes. For example, programs which have and use two
separate FS UIDs at the same time, or which attempt to make hardlinks to
files they don't own without CAP_FOWNER or root (should this just be
CAP_FOWNER? Is root now irrelavent?).

Hang on, when do any programs have 2 FS UIDs at the same time. . . .

I've yet to see this break anything on Ubuntu or Gentoo; Brad Spengler
claims this breaks nothing on Debian. On the other hand, this could
potentially squash the second most prevalent security bug.

> thanks,
> -chris

- --
All content of all messages exchanged herein are left in the
Public Domain, unless otherwise explicitly stated.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.5 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org

iD8DBQFCB8S0hDd4aOud5P8RAvYSAJ9zcGArfbC6i5uM1JW4ZHdELriUzACeOH/q
5ndpSdjporfnFAMK1OrMASE=
=XjWB
-----END PGP SIGNATURE-----
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:10    [W:0.685 / U:0.036 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site